Please don’t waste your time fitness training specifically for dance and then neglect to apply that training directly to your dancing! Instead, as you are doing sport specific exercises, think about how you will implement those techniques into your dance practice. For example, if you are working on straightening your arms while dancing: perform a set of triceps dips and realize that when your arm is straight at the top of that movement with your triceps engaged, that is what your upper arm should feel like during your dancing. Or even better, do a set of triceps dips and immediately get up to dance a step or a drill while engaging those upper arm muscles. This is one example of how you can make sure that your fitness training is very sport specific and not just a general workout by applying your training directly to your dancing.
That said, it is ideal to have a balanced training plan incorporating both general and sport specific training exercises. General exercises such as weighted squats or jump squats will help to improve athletic leg power, but unless you can apply that power to your jumps in dancing then these exercises serve no purpose. Sport specific exercises such as high toe walks in dance position will work to improve your cross, turnout, and toe height while dancing. However, you want to be careful with the amount of specific training that you do, as too much repetitive movement may lead to an overuse injury. Therefore, as you can see, a little general training for the athlete and a little sport specific training for the dancer combine to make the best possible balanced training plan. The final and most important step is to then understand how to apply both to your dancing.